Do We Love Kids? Five years ago, on a quiet, leisurely Thursday night, my husband and I sat at the dining room table with a yellow notepad, discussing when we should start having kids. "See, here's how it works," he said, drawing a graph. "With a dog, you put in a medium amount of work, and you get a medium amount of reward. If you were to, say, purchase a lion, you'd put in a lot of work, but you'd get pretty much no reward - and you might even get eaten. Horrible deal." He paused, drawing a straight...